Interesing.
Apparently, she WAS a spinoff, but had different creators.
http://en.wikipedia.org/wiki/Daria
She did start off as a character on Judge's "Beavis and Butthead", and I liked Daria series much better than "King of the Hill". Maybe it's a generational thing, I'm in my 20s.
It's too bad Beavis & Butt-head never did a cameo on Daria's show though. That would have been fun.